The present invention relates to a composition for permanently waving hair, applied in the first stage of permanent wave treatment of the hair, and more particularly to a permanent waving composition which has a reduced foul smell and is less damaging to the hair and moreover which can provide good wave to the hair.
Reducing and oxidizing agents have been generally used in the permament waving treatment of hairs such as human and animal hairs. The hair is put under stress, for example, by winding the hair on rods or rollers, and a waving lotion containing a reducing agent is applied to the wound or curled hair, whereby disulfide linkages of cystine included in keratin protein of the hair are cleaved to produce mercapto groups by means of the reducing agent. The waving lotion is an aqueous solution containing as a main component a reducing agent, e.g. mercaptans (namely thiols) such as thioglycolic acid and cysteine, to which a basic material such as ammonia, monoethanolamine or triethanolamine is usually added to adjust to pH 9.0 to 9.5. An aqueous solution of an oxidizing agent such as sodium bromate or hydrogen peroxide is then applied to the curled hair, thereby oxidizing the mercapto groups to form new disulfide linkages. Thus the permanent wave is formed.
Thioglycolic acid which has been widely used in practice as the reducing agent of the waving lotion, has a strong foul smell. Accordingly, the use of thioglycolic acid has a problem that not only the waving lotion itself has a uncomfortable smell, but also the smell remains on the hair even after the wavetreatment. Moreover, since thioglycolic acid and cysteine exhibit the reducing action only in an alkaline region, waving lotions using these reducing agents are kept alkaline. They have a problem that the hair is damaged and gives a feeling of being dry, since the hair is swollen by an alkali, so that a part of keratin protein is eluted and the remaining part of the hair undergoes physical and chemical changes.
It is an object of the present invention to provide a permanent waving composition which has no foul smell and does not cause any substantial damage of hairs.
A further object of the invention is to provide a permanent waving composition which can be used under a neutral or acidic condition.
These and other objects of the present invention will become apparent from the description hereinafter.